Even before genetic testing actually became available, fear that “genetic discrimination” would be practiced by employers and insurers was expressed, and calls were made for legislation to prevent this. However, there is no generally accepted definition of the term “genetic discrimination”. It is used differently by different persons; how it is used depends primarily on whose interests are at stake. Discrimination should be defined as unjustified differentiation. As genetic data may be used to predict morbidity and mortality, and thus expected costs in life and health insurance, the use of genetic testing results by private insurers in the calculation of premiums must be considered as justified. Scrutiny of the literature reveals that there are surprisingly few proven cases of genetic discrimination by insurance companies. On the other hand, we calculate the costs of adverse selection which would occur if the use of genetic tests were legally prohibited. We conclude that regulations based on codes of conduct with limits on insurance sums for which genetic test results are not used (like those in Germany or the United Kingdom) may enable affected persons to get insurance and, at the same time, allow insurers to limit adverse selection.